A lot of PLC controllers can certainly be unforgiving. I mentioned overflowing a 16 bit float point because that's exactly what happened at a waste water treatment plant I was called out to and the resulting regulatory fiasco that ensued probably cost the company tens if not hundreds of thousands of dollars.
replyI'd love to see more formal methods come to the field. Part of me says I'll return one day, maybe if AI kicks me out of my software field, but I'd really want to come back at a position I could healthily influence towards safety and correctness.
Seems like, here in the 21st century, one could reasonably have a model of the plant that tests could be executed against. Anything like that exist?
replyIt can become really complex. As an example, try to predict resonant frequencies on an entire plant full of rotating equipment. It can be done, but it often requires very expensive equipment and skilled technicians capable of using it to profile a plant. And that's just one potential problem you can run into.
replyWe're often talking about custom plants here, or plants made in very low volume. Making a simulator for that can be prohibitively expensive, since you can't amortize the cost. For particularly important/expensive plants it still sometimes gets done. Though note the simulator might not be able to capture all the nuances of the real world deployment, so it might not be sufficient.
replyMeanwhile having a separate copy of the plant is also not often viable, once the plants get to any kind of size.
edit: After having 'someone' fact check and remind me: there are quite a number of simulation tools available that can sometimes partially do the work.